In 1980, Arab terrorists took over the Iranian Embassy in London and threatened to kill them if their comrades weren’t freed from The Islamic Republic’s prisons.

It was a situation fraught with tension and suspense, largely covered live on British TV. The latest movie about it, “6 Days,” lacks that suspense and much of that tension. It’s such a middling entry in a well-developed genre that one must cast about for elements that worked well enough to justify making yet another movie about it, and using some of our favorite character actors — Mark Strong, Jamie Bell and Abbie Cornish — as they did.

And this New Zealand production provides one. Here’s a fact-based account that gets one important thing that every “surgical strike” fantasy ignores right. Little goes according to plan, people get hurt, bad guys don’t act predictably and all the rehearsals in the world can’t ensure the split-second precision the movies convince us that units like Seal Team Six provide with the effortlessness of Superheroes.

Jamie Bell portrays the SAS (Special Air Service) commando leader charged with giving the Thatcher government options for when things don’t pan out. Because Iran’s answer to the terrorist’s demands is that they “welcome all the hostages to be martyrs for the Islamic State.” If the embassy employees aren’t crazy about that, their visitors — including a British cop and a BBC reporter — are even less so.

Director Tao Fraser (“The Dead Lands”) gives the assault team the casual professionalism we’ve come to expect in movies about such folks. Gum snapping, their bosses quipping “Time to put theory into practice,” braced at the back door of the embassy, waiting to hear a shot that signals the bad guys have started shooting “Persians,” standing down every time the deadline gets pushed back.

We see the entire confrontation play out in government briefings, situation rooms where the negotiator bargains with the head terrorist (Ben Turner) who struggles to maintain discipline with his panicky comrades. The odd scene set inside the embassy does nothing to ratchet up tension and only reminds us how monocular this view of the crisis is.

Abbie Cornish plays a BBC reporter whose reputation was made covering this six day stand-off, but seems a token presence in the picture until its third act.

Bell long ago finished the job of butching up his screen persona — this isn’t his first soldier role — but it is Strong who has the picture’s best moments. Helpless to control what the military is planning, he narrows his focus to that which he hopes he can do just with his voice on a phone.

“Right here, right now,” he tells Salim (Turner) on the other end of the phone, “You and I can stop violence.”

There’s something odd about this ongoing cinematic infatuation with 1970s era terrorism. A big screen and small screen version of the Getty kidnapping, an oddly self-serving new version of “Israel’s Finest Hour,” “Seven Day in Entebbe,” coming out and this (which came out in late 2017), it’s hard to tie them together as a trend or embrace of the zeitgeist — a “talk tough, act tougher” age when “collateral damage” was tolerated by the likes of Reagan, Thatcher, Brezhnev, et al.

In that climate, the desultory “6 Days” can be appreciated for at least having the guts to show us what can go wrong.